1. Field of the Invention
The invention relates to a driving support device and a driving support method.
2. Description of Related Art
A driving support device is described In Japanese Patent Application 2010-18230 (JP 2010-18230). When a host vehicle enters an intersection, the driving support device determines whether it is possible for the host vehicle to avoid a collision with another vehicle using an estimated amount of time before the collision, which is so called “Time-to-Collision (TTC)”, and activates an airbag in a case where it is impossible for the host vehicle to avoid the collision. The driving support device uses information detected by a front radar to determine whether it is possible for the host vehicle to avoid a collision with a preceding vehicle, and uses information detected by a rear radar to determine whether it is possible for the host vehicle to avoid a collision with a following vehicle.
If the host vehicle traveling on a first road makes a direction change by turning right or left at a junction between the first road and a second road to enter the second road from the first road, the host vehicle will be followed by another vehicle traveling on the second road as a following vehicle. When the host vehicle enters the second road by turning right or left, a difference between a speed of the host vehicle immediately after the direction change and a speed of the other vehicle traveling on the second road toward the junction may be large and the other vehicle may get close to the host vehicle after the host vehicle completes the direction change. In this case, the driving support device described in JP 2010-18230 A uses information detected by the rear radar to determine whether the host vehicle needs a rear-side support for avoiding a collision with the other vehicle as the following vehicle. However, a detection range of the rear radar is limited to an area in the rear of the host vehicle, so the following vehicle will be detected only after the host vehicle enters the second road. This may cause a delay of a timing at which the rear-side support in relation to the following vehicle is provided.